How to Figure What Size of Air Conditioning Unit Is Needed for a Sunroom

Sunrooms should be bright, not hot.

While a sunroom brings a lot of sunlight into your house, it also can affect the comfort of your living space. Exposure to excessive heat decreases the efficiency of your home air conditioning system. Installing a room air conditioning unit in the sunroom supplements the work of your whole house system, and provides a more comfortable space. Proper sizing is key to purchasing the best unit for your needs.

1

Measure the length and width of the sunroom using a tape measure. For larger rooms, a laser measuring tool provides accurate measurements without the help of a second person.

2

Multiply the length and width to establish the square footage of the sunroom. For example, a room 25-feet long by 10-feet wide occupies 250 square feet of space.

3

Multiply the square footage of the room by 20 to establish the correct BTU rating for your sunroom. An average air conditioning unit requires 20 BTU for each square foot of living space to cool efficiently. Using the previous example, a 250-square-foot room requires a unit capable of 5,000 BTU.

Things You Will Need

Measuring tape

Laser measuring tool (optional)

Calculator

Tips

Factors such as high ceilings, lack of window coverings and local climate may necessitate an increase of the calculated BTU.

Units with an adjustable airflow control can allow you to direct cool air into a particular section of the room.

Warning

About the Author

Jeff O'Kelley is a professional photographer and writer, currently based in the Tampa, Florida area. His images and words have been featured by websites and publications such as CNN, Creative Loafing and Tampa Bay Times. O'Kelley holds associate degrees in telecommunications and website design from St. Petersburg College.